Effect of Interface Coupling on the Energy Spectrum of Triple-Layer Film. Interface-Localized Modes

Numerical results of a new (interface-rescaling) theory of normal excitations in a triple-layer film are reported. The film is modelled by three one dimensional finite chains coupled together; the coupling across the interface is properly taken into account. The formation process of the film energy spectrum as a result of interface (i.e. inter-chain) coupling is studied, and the exact conditions for the existence of interface-localized modes are established.